1. Field of the Invention
The present invention relates to an array of three nested sets of electromagnetic coils. A common axis of two electromagnetic coils of one set is orthogonal to a common axis of two electromagnetic coils of each of the other two sets. The present invention also relates to a test device of which the array is a part.
2. Description of Related Art
U.S. Pat. No. 4,587,490 shows two coaxially aligned sets of electromagnetic coils. Two coils of one set lie between two coils of the other set.
U.S. Pat. No. 3,771,048 shows a single set of electromagnetic coils. The two axes of the two coils are coaxial. The coils produce a substantially uniform field in the general vicinity surrounding an axis through the coils. The coils are used as a part of a tester.
A thesis published in 1962 shows two sets of electromagnetic coils. One set of coils encompasses the other set of coils. A common axis of one set of coils is perpendicular to a common axis of the other set of coils. The diameters of the coils of one set are equal to the diameters of the coils of the other set. The two sets of coils are for the purpose of performing a physics experiment rather than being part of a tester. The thesis is in the Physics Library of the Ohio State University. The title of the thesis is "Spin Relaxation Time Of Optically Pumped Rubidium Vapor". The author is Edward W. Fisher.
The present invention relates to an array of three sets of electromagnetic coils. A common axis of one set of coils is orthogonal to a common axis of each of the other two sets. Further, a common diameter of one set of coils is less than a common diameter of an adjacent set of coils, so that the three sets of coils can nest.
The array of sets of coils can essentially neutralize, in three dimensions, the effects of extraneous magnetic fields, such as the earth's magnetic field, within the space encompassed by the array. The neutralization is essentially omni-directional. The coils can produce uniform magnetic fields in the directions of the three orthogonal common axes, within the space encompassed by the array.
The array is compact in its physical dimensions since the three sets of electromagnetic coils nest together. As the distance from the center of the array increases, the diameter of each successive set of coils increases.
The present invention also relates to a test device of which the disclosed array is a part.